The invention relates to the field of microwave switches, and more particularly to a microwave switching power divider for selectively dividing and switching microwave energy between a source of microwave power and a plurality of microwave devices such as antenna elements.
Modern microwave antenna systems, such as those used in multi-element spherical arrays and satellites, are characterized in that a single source of microwave energy is selectively coupled to one or more of the antenna elements at the same time to perform a beam forming function. Each actuated element must be fed with microwave energy having substantially equal amplitudes and uniform phase, regardless of the number of elements so actuated. Otherwise, power transfer to the antenna elements is inefficient.
Conventional multi-element microwave power dividing and switching devices utilize a power divider to distribute the microwave energy to a group of microwave devices such as an array of antenna elements, and a plurality of single-pole multi-throw switches, one for each group of elements, to select one of the antenna elements of the group as the output element. Diode switching devices have been used to replace conventional coaxial cable multi-pole switches to reduce insertion losses associated with these mechanical switches.
Such prior art antenna switching devices are limited in beam-forming performance, because it is often necessary to actuate two or more antenna elements within a particular group of elements to form a desired beam pattern. In addition, large numbers of switches and interconnecting cables are used in such devices resulting in increased insertion losses and decreased output power and efficiency. The complexity and bulk of conventional microwave power dividing and switching devices preclude their use in satellite systems where weight and size must be minimized.